Cutting tool device for machine tool

ABSTRACT

A cutting tool device for a machine tool having a cutting tool ( 2 ) for cutting a plane fixed to the tip end of a rotating shaft ( 1 ) and provided with a suction cover ( 10 ) covering airtightly the surrounding portions except for a tip face (a), of the cutting tool ( 2 ), wherein a hood ( 19 ) is attached to the tip opening edge of the suction cover ( 10 ) so as to further extend forward therefrom and to be displaceable longitudinally within a limited range, and an urging means ( 24 ) for urging the hood ( 19 ) forward is provided, whereby chips (w 1 ) produced by the cutting tool ( 2 ) can be positively sucked and discharged when the tool is used in any of a roughing step and a finishing step.

FILED OF THE INVENTION

The present invention relates to a cutting tool device of a machine toolthat can rationally remove chips.

BACKGROUND OF THE INVENTION

The Japanese patent No. 2535964, for example, discloses a cutting tooldevice of a machine tool having a fraise cutter fixed to the tip of arotating shaft and provided with a suction cover covering thesurrounding portions, except for the tip face, of the cutter.

This cutting tool device moves in a direction transverse to the rotatingshaft during use. The fraise cutter machines a work surface of aworkpiece in a plane during its movement. On the other hand, air insidethe suction cover is drawn by an air suction device arranged separatelyand is eliminated in another place. Because of this elimination, an airflow generated around the fraise cutter acts to continuously dischargeto the other place chips produced by machining with the fraise cutter.

In the above machine tool, plural kinds of cutting tool devices, in eachof which the longitudinal distance between the tip face of the fraisecutter and the tip face of the suction cover is suitably changed, areusually prepared for various machining steps, such as a roughing stepand a finishing step, in relation to an uneven size of the work surfaceand the amount of material to be cut with each pass of a cuttingelement. These cutting tool devices are used so that exchanging of thedevices may be carried out for each machining step to the end of thecutting work.

The above-described conventional cutting tool device is uneconomical inpreparing different cutting tool devices for each machining step of thework. Besides, these devices need to be exchanged during the machining,thereby taking more time, as well as having a disadvantage in keepingcutting accuracy. An object of this invention, therefore, is to proposea cutting tool device for a machine tool that can overcome the aboveproblems.

SUMMARY OF THE INVENTION

To achieve the above objects, the present invention comprises a cuttingtool for cutting a plane fixed to the tip of a rotating shaft, and asuction cover covering airtightly surrounding portions, except for thetip face of the cutting tool, wherein a hood is attached to the tipopening edge of the suction cover so as to further extend forwardtherefrom to be displaceable longitudinally within a limited range, andan urging means for urging the hood forward is provided.

According to this structure, the hood retreats upon touching an unevenwork surface of a workpiece without disturbing the cutting step. The tipface of the hood can come very close to the uneven face during not onlya finishing step but also a roughing step without having its positionadjusted. Because of the effect of this hood, one cutting tool devicecan be utilized both in a roughing step and a finishing step.

The present invention has structures as follows.

When the hood is located at a forward restricted position in itslongitudinal displaceable range, the tip face of the hood is set apartfrom the cutting edges of the cutting tool by about 0.5 mm–3.0 mm.According to this structure, the cutting tool device can be utilizedintact in both a practical roughing process and a practical finishingprocess.

Besides, the front restricted position of the hood in the longitudinaldisplaceable range can be changed. According to this structure, the hoodcan always act in the best condition on a variety of workpieces havingdifferent uneven faces and any amount of cut material for each pass of acutting element.

Moreover, the tip face of the hood is tapered outwardly along its radialdirection. According to this structure, when the tip face of the hoodcontacts the uneven work surface, the hood stops being caught easily andunevenly on the work surface, and can receive greater upward forcesmoothly, thereby enabling high quality cutting.

Furthermore, the rotating shaft, the cutting tool, the suction cover,the hood and the urging means are formed into an independent integralstructure, which is detachable from a main spindle of the machine tool.According to this structure, the cutting tool devices can be easilyexchanged with another one, and their removal is carried out by anautomatic cutting tool device exchanging machine.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view showing a part of a cutting tooldevice of a machine tool according to this invention.

FIG. 2 is a partially front view of a cutting tool in theabove-mentioned.

FIGS. 3A–3B are schematic views showing the actions of the above cuttingtool device: FIG. 3A shows a state right before a machining processstarts; FIG. 3B shows the surrounding portions of the front end side ina main spindle traveling direction of a sleeve during machining; andFIG. 3C shows the surrounding portions of the back end side in a mainspindle traveling direction of the sleeve during machining.

DESCRIPTION OF PREFERRED EMBODIMENTS

First, the cutting tool device is described in detail. Numeral 1 is anarbor of a rotating shaft. The arbor 1 includes a parallel body 1 a, onthe front-end face of which is provided a protruding portion 1 b havinga round section, on the periphery of the front end of which is providedmale screw 1 c, and on the back end of which is provided the firstflange 1 d. Besides, the second flange 1 f is provided on the back ofthe first flange 1 d through a parallel body 1 e, and a taper shank 1 gis provided at the back thereof. Moreover, a pulling stud 1 h protrudingbackward is provided on the back-end face of the taper shank 1 g. Inthis case, 1 i is a circular groove body having a trapezoid sectionprovided in the longitudinal middle of the second flange 1 f, which isgripped by a tool-exchanging machine not shown.

Numeral 2 is a fraise cutter as a cutting tool for cutting a plane,comprising a stepped cylindrical cutter body 2 a, on an outercircumference of the tip face a of which are longitudinally fixed atlimited intervals in circumferential direction chips 3 that are squarein side view, at the center of which is provided a stepped internal hole2 b, and on the back face of which is provided an interfittedindentation 2 c to receive a detent key 4 fixed on the tip face of theparallel body 1 a of the arbor 1.

Here, as shown in FIG. 3A, a front cutting edge 3 a of the chip 3 servesas a front edge of the cutter body 2 a, whereas a side cutting edge 3 bthereof serves as a side edge thereof.

The fraise cutter 2 is fixed to the tip of the arbor 1 in the followingmanner. The aftermost part of the internal hole 2 b of the cutter body 2a is externally engaged with the protruding body 1 b of the arbor 1, andthe detent key 4 fixed on the tip face of the arbor 1 is internallyengaged with the interfitting indentation 2 c. Besides, a flanged bush 5is internally engaged with a middle part of the internal hole 2 b of thecutter body 2 a, and a fixing bolt 6 is inserted into an inner hole ofthe bush 5. Then, a threaded portion of the bolt 6 is screwed into afemale screw formed on the protruding body 1 b of the arbor 1.

Numerals 7 a, 7 b are a pair of front and back ball bearings provided onthe outside of the parallel body 1 a of the arbor 1. A back-end face ofan inner ring for the back ball bearing 7 b is engaged with the firstflange 1 d, whereas a front-end face of an inner ring for the front ballbearing 7 a is pressed against a nut 8 screwed to the male screw 1 c ofthe parallel body 1 a through a spacer ring and a circular plate 9.Thus, longitudinal positions of the ball bearings 7 a, 7 b for the arbor1 are restricted. Besides, the circular plate 9 is to prevent the nut 8from being loosened.

Numeral 10 is a suction cover, comprising a stepped cylindrical body 10a and a suction passage 10 b. The stepped cylindrical body 10 a coversthe surrounding portions in an airtight manner, except for the tip face‘a’ of the fraise cutter 2, and the suction passage 10 b extendsrearward so as to protrude sideways from a part of the periphery of thecylindrical body 10 a.

The cylindrical body 10 a includes a base body b1 having an inner holewhich is externally engaged with the ball bearings 7 a, 7 b, and a headbody b2 having an inner hole of relatively large diameter for encirclingthe fraise cutter 2. A back circular securement plate 11 is bolted tothe back face of the base body b1 to prevent forward displacement of thesuction cover 10 at an outer ring of the back ball bearing 7 b byprotruding inward of the inner hole of the suction cover. In addition, afront circular securement plate 12 is bolted to a marginal step betweenthe inner hole of the base body b1 and the inner hole of the head bodyb2 to prevent backward displacement of the suction cover 10 at the frontface of the nut 8. Moreover, a sealing means 13 is provided to seal theintermediate between the circular securement plate 12 and the cutterbody 21 in an airtight manner.

The above suction passage 10 b is provided with a suction pass c whichcommunicates with the inner hole of the head body b2. The suction pass cis led sideways and rearward from a portion c1 communicating with theinner hole of the head body b2 to a protruding face d which extends theback face of the base body b1 sideways. A connector 14 is fixed to theback end of the suction pass c, and then a circular sealing member 15 isfitted to a back edge of the connector 14.

A detent means for the suction cover 10 is provided between theconnector 14 and the back circular, secure plate 11 on the protrudingface d. The detent means comprises a guiding hole e formed on theprotruding face d, a sliding shaft 16 inserted into the guiding hole e,and a compressed spring 17 provided between the sliding shaft 16 and thebottom of the guiding hole e. Besides, an engaging plate 16 a and a cap18 are bolted to the tip of the sliding shaft 16. Moreover, the outerend of the engaging plate 17 is engaged with a vertical groove f formedon the outer periphery of the connector 14, whereas the inner end of theengaging plate 16 a is engaged with a vertical groove g formed on thecircular groove body 1 i of the second flange 1 f.

Here, an explanation follows concerning the action of the engaging plate16 a. When the engaging plate 16 a is free, the sliding shaft 16 ispushed backward by the compressed spring 17. This backward movement isrestricted by an interaction between the outer end of the engaging plate16 a and the back end of the vertical groove f. In this state, the innerend of the engaging plate 16 a is located at the upper end of thevertical groove g, thereby restricting rotations of the arbor 1.However, if the sliding shaft 16 is pushed forward for a limiteddistance by some other means, the inner end of the engaging plate 16 ais located in the circular groove body 1 g, thereby releasing the arbor1 to rotate.

Next, an explanation follows concerning the characteristic constructionof this invention.

A sleeve 19 as a hood is attached to the tip opening edge of the abovesuction cover 10 so as to extend further forward therefrom and to bedisplaceable longitudinally within a limited range. More concretely, acircular guiding groove h is provided on the above-mentioned tip openingedge, and a fitting part of the back of the sleeve 19 is inserted intothe guiding groove h so as to be slidingly displaceable longitudinally.Besides, a variable device 20 is provided so as to restrict slidingdisplacement of the sleeve 19 within a limited range and to displace therange longitudinally.

The variable device 20 comprises a nut 21 engaged with a male screw iformed on the outer periphery of the tip opening edge of the suctioncover 10, and engaging pieces 22 bolted on the front-end face of the nut21 at fixed intervals in its circumferential direction. The tip of eachengaging piece 22 is engaged with a circular groove j of a limited widthprovided on the outer periphery of the sleeve 19. In this case, fixingscrews 23 are provided through the thickness of the nut 21 at fixedintervals in its circumferential direction to fix the nut 21 at asuitable position on the male screw i.

Besides, an urging means is provided so as to urge the sleeve 19forward. Concretely, compressed springs 24 are provided between theback-end face of the sleeve 19 in the guiding groove h and the bottomface thereof at fixed intervals in a circumferential direction of theguiding groove h. These compressed springs 24 act so that the sleeve 29is displaced forward with their spring effect. When the sleeve 19 isfree, they act so as to keep the sleeve 19 at the front restrictedposition in its moving range by pushing a back wall k1 (in FIG. 3) ofthe circular groove j against the engaging pieces 22 on the nut 21,which is fixed at a suitable position on the male screw i.

Moreover, a tip face m of the sleeve 19 is tapered outwardly in a radialdirection thereof. When the sleeve 19 is located at the front restrictedposition, the tip face m of the sleeve 19 is set apart from the cuttingedges 3 a of the chips 3 by about 0.5 mm–3.0 mm.

The cutting tool device has the above-described construction. Thecomponents are connected with each other to form an integral structure.

Next, a main spindle for installing on the above cutting tool devicewill be explained with reference to FIG. 1 as follows. Numeral 100 is amain spindle supporting member, 101 is a main spindle rotatablysupported by the main spindle supporting member 100 through ballbearings 102 a, 102 b, and 103 is a front circular member bolted to atip face of the main spindle supporting member 100. Numeral 104 is acircular-covering member of small diameter externally fixed to the tipof the main spindle 101 to cover a space between the main spindle 101and the front circular member 103. Numeral 105 is a protrudingsupporting member bolted to a front face of the front circular member103 so as to keep away from the circular-covering member 104.

As shown in FIG. 2, a pair of forward protruding bodies n1, n2 areprovided on the forward main spindle 101 side of the protrudingsupporting member 105. The protruding bodies n1, n2 are located atplaces shown in oblique lines, having the cap 18 therebetween. A suctionopening c2 is provided outside the protruding bodies n1, n2, incorrespondence with the connector 14. To the back end of the suctionopening c2 is connected one end of an air suction pipe 106. Besides, theother end of the air suction pipe 106 is connected to a not-illustratedair suction device.

Next, an explanation follows concerning use and actions of the abovecutting tool device.

The above cutting tool device is placed on a storage stand, for example,in a fixed posture, when it is not used. On installing the cutting tooldevice on the machine tool, the cutting tool device is carried beforethe main spindle 101 by a not-illustrated tool exchanger, and then thetaper shank 1 g is pushed into a center hole of the main spindle 101, ashown in FIG. 1.

Next, the pull stud 1 h is pulled backward by a not-illustrated drawingmechanism. In consequence, the arbor 1 is fixed to the main spindle 101firmly, and the cutting tool device is perfectly fixed in a workingposition. In this state, an inner hole of the connector 105 is connectedwith the suction opening c2 of the protruding supporting member 105 inan airtight manner through the circular-sealing member 15. The cap 18for preventing rotations of the suction cover 10 is interfitted betweena pair of the protruding bodies n1 and n2, and pushed forward for alimited distance against the compressed spring 17. In consequence, thesuction cover 10 is fixed, being restricted from its rotation around themain spindle 101. The inner end of the engaging plate 16 a is located inthe circular groove body 1 i, thereby releasing the arbor 1 to rotatearound the center of the main spindle 101.

To detach the cutting tool device from the working position and returnit to the storage stand, reverse actions are carried out.

Cutting a workpiece w with the cutting tool device fixed in a stateshown in FIG. 1 is carried out in the following manner, for example. Theworkpiece w is fixed on a not-illustrated working table, and thenot-illustrated air suction device is operated. Then, the main spindleis rotated.

Next, as shown in FIG. 3A, the main spindle 101 is moved forward to asuitable position so that the fraise cutter 2 can cut the work at afixed height. Then, the main spindle 101 is rectilinearly displaced in adirection u perpendicular thereto. As shown in FIG. 3B, the fraisecutter 2 cuts the workpiece w flatly with the front cutting edge 3 a andthe side cutting edge 3 b thereof, while it is moving on. During thisprocess, chips w1 are continuously produced.

On the other hand, the air pass c and chip discharging space p betweenthe fraise cutter 2 and the suction cover 10 are made into a vacuum.Accordingly, air bursts into the chip discharging space p through anopening between the tip face m of the sleeve 19 and a work surface s ofthe workpiece w. This inflow of the air continuously discharges thechips w1 produced by the fraise cutter 2 into some other place throughthe chip discharging space p, the air suction pass c, and the airsuction pipe 106.

The longitudinal movement of the sleeve 19 is restricted by an annulargroove j thereof. Since its front restricted position is relatively lowrelative to irregularities of the work surface s in the roughing step, apart 19 a of the tip face m of the sleeve 19 is in contact withconvexities of uncut surface s1. Here, the part 19 is in front of themain spindle moving in its progressive direction. The uncut surface s1gives a boosting force to the tip face m of the sleeve 19, and thereforethe part 19 a of the sleeve 19 is pushed back against the compressedspring 24. On the other hand, as shown in FIG. 3C, a part 19 b of thesleeve 19 remains in the front restricted position without contactingwith a cut surface s2 after the main spindle moving in its progressivedirection. The sleeve 19 moves in the direction u perpendicular to themain spindle, being in an inclined and retreated state. Accordingly, thesleeve 19 can move with the spindle 101 and the suction cover 10 withoutbeing caught by the work surface s of the workpiece while keeping thedistance with it between the sleeve and the work surface small. When thedistance between the tip face m of the sleeve 19 and the work surface sis small, inflow speed of the air into the suction cover 10 anddischarge capacity of the chip w1 are increased. Besides, since the tipface m of the sleeve 19 is tapered outwardly in a radius directionthereof, the sleeve 19 can move smoothly while in keeping touch with theconvexities. Accordingly, interference between the sleeve and theworkpiece is avoided more certainly.

During a finishing process, since the irregularity of the work surface sand an amount of material removed during each pass of a cutting elementare small, the sleeve 19 can move forward with the spindle 101 and thesuction cover 10, generally without contacting with the work surface s.However, as described above, since the restricted position of the sleeve19 by the annular groove j is relatively low relative the work surfaces, the sleeve 19 can keep the distance with the work surface s smallduring this process. If there is an unexpectedly large burr on the worksurface s, the sleeve 19 is inclined and retreated according to theroughing process. Accordingly, the distance between the sleeve 19 andthe work surface of the work w is maintained as small as possible,thereby increasing inflow speed of the air into the suction cover 10 aswell as discharge capacity of the chips.

It may be necessary to change the front restricted position of thesleeve 19 by the annular groove j according to degree of the uneven worksurface s of the work w or an amount of cuts per 1-time cutting of thefraise cutter 2. In this case, the fixing screw 23 is operated to changea longitudinal position of the nut 21 on the male screw i.

In the above embodiment, a sectional form of the passage of the hood 19is not restricted to a complete round, but it can be a suitable form.Besides, a plate spring or a folded linear spring, or even a fluidpressure utilizing means can be used as an urging means instead of thespring 24. Moreover, a milling cutter or an end mill cutter can be usedas a cutting tool for cutting a plane instead of the fraise cutter 2.

According to thus constructed invention, the chips can be effectivelydischarged during both the roughing step and the finishing step.Therefore, it is unnecessary to prepare different mechanisms for eachmachining step, which is very economical. Besides, since it isunnecessary to change the cutting tools when moving into the nextmachining step, time for treatment is shortened and working efficiencyincreases remarkably. Moreover, it can be prevented to decrease accuracydue to exchanging the cutting edges. Furthermore, since the hood iscontacted between the uncut surface and the cut surface of the work inan inclined state, a space between the tip face of the hood and the worksurface of the work becomes small. Accordingly, recovery percentage ofthe chips during a roughing step, for example, can be increased up to95%.

The present invention can be conveniently utilized in most usualroughing and finishing processes.

The present invention can have suitable suction capacity of the chipsfor any workpiece having a different uneven work surface or for a broadmachining operation requiring different amounts of cut material for eachpass of a cutting chip 3.

The tip face of the hood receives great upward force smoothly bytouching the uneven work surface of the workpiece, thereby ensuring thehood's retreat as well as its prevention from being caught by the unevenwork surface. Besides, when the hood moves along the workpiece,vibrations hardly arise due to their contact, thereby effecting a cut ofhigh quality.

Other cutting tool devices can be applied to the present invention.Besides, the present invention can contribute to forming a structuredetachable by an automatic tool-exchanging device.

1. A cutting tool device for a machine tool comprising: a cutting tooladapted to produce a plane surface by movement parallel to the planesurface being produced, said cutting tool being fixed to a tip end of arotating shaft and having cutting edges; and a suction cover coveringand surrounding the cutting tool in an airtight manner, except for a tipface of the cutting tool, wherein a hood is attached to a forward end ofthe suction cover, around an opening of the suction cover, so as toextend farther forward from the suction cover to be displaceable withina limited range in a direction parallel to the direction in which thehood extends farther forward from the suction cover, wherein the hoodhas a tip face set apart from the cutting edges of the cutting tool byabout 0.5 mm–3.0 mm when the hood is located at a forwardmost positionin its limited range; and means for urging the hood forward, said urgingmeans comprising springs positioned at fixed intervals from one anotheraround the circumference of the opening of the suction cover.
 2. Acutting tool device for machine tool as set forth in claim 1: whereinthe forwardmost position of the hood is adjustable.
 3. A cutting tooldevice for machine tool as set forth in claim 2: wherein the hood has atip face tapered outwardly in its radial direction.
 4. A cutting tooldevice for machine tool as set forth in claim 2: wherein the rotatingshaft, the cutting tool, the suction cover, the hood, and the urgingmeans are integrated into one independent structural object; and whereinsaid structural object is detachable from a main spindle of the machinetool.
 5. A cutting tool device for machine tool as set forth in claim 1:wherein the hood has a tip face tapered outwardly in its radialdirection.
 6. A cutting tool device for machine tool as set forth inclaim 5: wherein the rotating shaft, the cutting tool, the suctioncover, the hood, and the urging means are integrated into oneindependent structural object; and wherein said structural object isdetachable from a main spindle of the machine tool.
 7. A cutting tooldevice for machine tool as set forth in claim 1: wherein the rotatingshaft, the cutting tool, the suction cover, the hood, and the urgingmeans are integrated into one independent structural object; and whereinsaid structural object is detachable from a main spindle of the machinetool.
 8. A cutting tool device for machine tool as set forth in claim 1,wherein a guiding groove is defined in the suction cover, around theopening of the suction cover, and said springs are positioned in saidguiding groove.
 9. A cutting tool device for a machine tool comprising:cutting means for producing a plane surface by movement parallel to theplane surface being produced, said cutting means being fixed to a tipend of a rotating shaft and comprising cutting edges; a suction covercovering and surrounding the cutting means in an airtight manner, exceptfor a tip face of the cutting means, wherein a hood is attached to aforward end of the suction cover, around an opening of the suctioncover, so as to extend farther forward from the suction cover to bedisplaceable within a limited range in a direction parallel to thedirection in which the hood extends farther forward from the suctioncover, wherein the hood has a tip face set apart from the cutting edgesof the cutting means by about 0.5 mm–3.0 mm when the hood is located ata forwardmost position in its limited range; and means for urging thehood forward, said urging means comprising springs positioned at fixedintervals from one another around the circumference of the opening ofthe suction cover.
 10. A cutting tool device for machine tool as setforth in claim 9: wherein the forwardmost position of the hood isadjustable.
 11. A cutting tool device for machine tool as set forth inclaim 10: wherein the hood has a tip face tapered outwardly in itsradial direction.
 12. A cutting tool device for machine tool as setforth in claim 10: wherein the rotating shaft, the cutting mean, thesuction cover, the hood, and the urging means are integrated into oneindependent structural object; and wherein said structural object isdetachable from a main spindle of the machine tool.
 13. A cutting tooldevice for machine tool as set forth in claim 9: wherein the hood has atip face tapered outwardly in its radial direction.
 14. A cutting tooldevice for machine tool as set forth in claim 13: wherein the rotatingshaft, the cutting means, the suction cover, the hood, and the urgingmeans are integrated into one independent structural object; and whereinsaid structural object is detachable from a main spindle of the machinetool.
 15. A cutting tool device for machine tool as set forth in claim9: wherein the rotating shaft, the cutting means, the suction cover, thehood, and the urging means are integrated into one independentstructural object; and wherein said structural object is detachable froma main spindle of the machine tool.
 16. A cutting tool device formachine tool as set forth in claim 9, wherein a guiding groove isdefined in the suction cover, around the opening of the suction cover,and said springs are positioned in said guiding groove.